Just dipping my toe in the water. I'm in the process of putting a 454 and 4L80E from a 95 3/4 ton in my '78 C10. I'm melding the 95 harness with a 91 Suburban engine harness, dash harness, and cluster. I'm pretty confident I have that end of it under control, but am a little apprehensive about the tuning since I've never done any...I'm here to learn.
Thanks!
Travis
Welcome.
Sounds like a good starter project. Do you have any pictures?
If the engine is stock and ran well in the '95 it should run well in the '78. You can take small steps in the beginning and if you do something that doesn't work out you can always go back to the last good file.
Thanks! It's completely stock and ran extremely well in the '95. Not terribly quick, but used no oil and was entirely reliable. I drove the '95 for about a year before I knocked it in the head for the powertrain.
It's actually going pretty smoothly; not a difficult adaptation at all. My goal is to do the conversion as I think GM would have done it if they had built a '78 with TBI and 4L80E. The engine wiring harness is the most tedious part so far, but not really difficult. I learned an awful lot about them having to study what each signal does. When I'm done, the engine and transmission shouldn't know that they woke up in a different body. Finding a '91 Suburban donor was very helpful since it's TBI and most of the body components are in the same locations. It even gives me an electronic speedometer that fits my dash. I'll mount the VSSB in the stock location for the '91 DRAC and the PCM will go in the same location as on the '91, although that will require a bit more work. I'm toying with the idea of moving the RWAL from the '91 onto the '78 as well since all the wiring will be in place.
The biggest technical challenge so far has been the fuel system. The '78 has dual tanks with a solenoid operated changeover valve. I didn't want to give up the dual tanks and didn't want to have to change to '87 tanks for their baffles. I came up with the idea of using two fuel pumps; the first one draws from the selected tank through the changeover valve and pumps into a vertically oriented canister filter. It has a return line drilled and tapped in the very top of the casting so that any air, or excess fuel, can return to the tank, again through the changeover valve. A dip tube in the outlet of the filter draws fuel from the very bottom of the inside of the filter. This gives me about a quart of reserve fuel in the filter to avoid starvation issues when the fuel level is low in the tank. A second frame-mounted pump draws from this filter's outlet and feeds the TBI, through the normal filter of course. The return line from the TBI's regulator is tee'd into the return line in the filter/sump for return to the appropriate tank through the fuel changeover valve. I doubt very much I'm the first to come up with this, but I think it will serve my purpose well. It also has the advantage, since there is a second pump to pressure up the TBI, I can accommodate the high pressure that the '95 wants or change to a vortec or ls up the road if I want to. I have a Whipple supercharger kit that I picked up while back that I'm thinking I might put on it for the heck of it, but I want to get it sorted out in stock form first. And I'm not all that enthused about the supercharger so it might never happen. I'm just kind of playing it by ear.
I haven't taken any pictures yet; it doesn't look like much. The '78 sat out pretty much abandoned for the last 15 or so years at a friend's shop. I've been trying to buy it from him for years. He finally let me talk him into it about 2 years ago. I haven't done much to it yet; just now getting started. I'm getting old enough to be thinking of retiring in not too many years and my plan at that time is to sell everything and live full time in my motorhome. I'm hoping to have the '78 completely restored by then and it will be my only transportation. We'll see.
Anyway, I've learned a lot here already and I really appreciate the site and the warm welcome.
Travis
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